The present invention relates to an electron measurement apparatus such as for example an electron holography apparatus and an electron microscope.
In the field of transmission type electron microscope, there has already been known a technique for adjusting excitation of electron magnetic lenses such that the position of an image to be observed will not be rotated when the magnification is changed, and standard electron microscopes have the above function. Also, as described in "Rotary Electron Biprism" ("Electron Microscope", Vol. 10, No. 2, 1975, page 111), a technique has been known by which the electron biprism is rotated by rotating a pulley pulled by a spring.